Canna was a Breton princess,
traditionally a daughter of Tewdwr Mawr
ap Emyr Llydaw. This man, however, appears to have actually been the
grandson, rather than the son, of Emyr Llydaw (Budic
II) and was probably the lady's brother. She married her cousin, Prince
Sadwrn, a man somewhat her elder, and, together, they became the
parents of St. Crallo.

The family moved to South Wales,
where Sadwrn got religion and appears to have deserted Canna in order to
become a hermit on Anglesey, where he later died. Canna soon remarried to
Alltu Redegog, a descendant of King Cadrod
Calchfynedd, by whom she had
another son, St. Elian Geimiad (the Pilgrim). Depictions of her in
art holding a staff which miraculously flowers may suggest a lost legend,
similar to that of St. Ciaran's mother, whereby, upon feeling the pangs of
childbirth, she grasped at a dry rowan stick which immediately burst into
leaf. Which child this would refer to is unknown.

In retirement, Canna became a nun,
founding churches at Llangan and Llanganna, and possibly Canton, in
Glamorganshire. Her main residence was at Llangan in Caermarthenshire,
where her stone 'chair' an still be seen inscribed with her name. The
nearby Fynnon Ganna (Canna's Holy Well) was, for centuries, a popular
place of pilgrimage.

Canna's festival is celebrated on
25th October. She should not be confused with St.
Cain ferch Brychan or St. Caen ap Caw.